diff --git a/filecaster-derive/src/from_file.rs b/filecaster-derive/src/from_file.rs
index 4ba1726..e1509e5 100644
--- a/filecaster-derive/src/from_file.rs
+++ b/filecaster-derive/src/from_file.rs
@@ -174,13 +174,13 @@ fn parse_default(list: &MetaList) -> Result<Option<Expr>> {
             let value = meta.value()?;
             let expr = value.parse::<Expr>()?;
 
-            if let Expr::Lit(expr_lit) = &expr {
-                if let Lit::Str(lit_str) = &expr_lit.lit {
-                    default_expr = Some(parse_quote! {
-                        #lit_str.to_string()
-                    });
-                    return Ok(());
-                }
+            if let Expr::Lit(expr_lit) = &expr
+                && let Lit::Str(lit_str) = &expr_lit.lit
+            {
+                default_expr = Some(parse_quote! {
+                    #lit_str.to_string()
+                });
+                return Ok(());
             }
             default_expr = Some(expr);
         }
diff --git a/filecaster/examples/simple.rs b/filecaster/examples/simple.rs
index 17f3df1..008d833 100644
--- a/filecaster/examples/simple.rs
+++ b/filecaster/examples/simple.rs
@@ -40,9 +40,9 @@ fn main() {
     // Example assertions (adjust based on your actual file contents)
     assert_eq!(json_data.key, "json key".to_string());
     assert_eq!(json_data.number, 123);
-    assert_eq!(json_data.exists, false); // `bool::default()` is `false`
+    assert!(!json_data.exists); // `bool::default()` is `false`
 
     assert_eq!(toml_data.key, "default key".to_string());
     assert_eq!(toml_data.number, 456);
-    assert_eq!(toml_data.exists, true);
+    assert!(toml_data.exists);
 }
diff --git a/filecaster/tests/ui/enum_not_supported.stderr b/filecaster/tests/ui/enum_not_supported.stderr
new file mode 100644
index 0000000..2247272
--- /dev/null
+++ b/filecaster/tests/ui/enum_not_supported.stderr
@@ -0,0 +1,6 @@
+error: FromFile only works on structs.
+       Enums are not supported.
+ --> tests/ui/enum_not_supported.rs:4:6
+  |
+4 | enum MyEnum {
+  |      ^^^^^^
diff --git a/filecaster/tests/ui/invalid_attr.rs b/filecaster/tests/ui/invalid_attr.rs
deleted file mode 100644
index 5dc332f..0000000
--- a/filecaster/tests/ui/invalid_attr.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-use filecaster::FromFile;
-
-#[derive(FromFile)]
-struct MyStruct {
-    #[from_file(unknown)]
-    field: i32,
-}
-
-fn main() {}
diff --git a/filecaster/tests/ui/tuple_struct_not_supported.stderr b/filecaster/tests/ui/tuple_struct_not_supported.stderr
new file mode 100644
index 0000000..5b42657
--- /dev/null
+++ b/filecaster/tests/ui/tuple_struct_not_supported.stderr
@@ -0,0 +1,6 @@
+error: FromFile only works on structs with *named* fields.
+       Tuple structs and unit structs are not supported.
+ --> tests/ui/tuple_struct_not_supported.rs:4:8
+  |
+4 | struct MyTuple(i32, String);
+  |        ^^^^^^^